Jonathan Newell finds out how the University of Central Lancashire is taking Graphene to new heights for future aerospace applications.
The development of aerospace materials has taken us from the first wood and fabric constructed airframe, through various metals before composite materials and carbon fibre took over.
Rather than a gradual evolution, the industry has gone through a number of breakthrough changes that marked significant improvements in flight technology. However, the use of new materials has always been met with some trepidation. Chiefs at British Aerospace (now BAE Systems) stated that aeroplanes would never be made from plastic and yet within less than a decade, carbon fibre reinforced plastic was being used for non-safety critical flight components.
At the time, BAe published its roadmap to carbon fibre and flew a military Jet Provost aircraft with carbon fibre components. The entire carbon fibre demand has since risen from the initial 500kg in those early days to the 250 thousand tonnes currently consumed.
A step beyond
The industry is constantly researching new materials and nanotechnology has provided the means to take the next step beyond carbon fibre composites in the shape of Graphene. This amazing material is made up of atom thin layers of graphite built up to a maximum of ten layers. The resulting material is ultra-light, two hundred times stronger than steel, flexible and with excellent thermal and electrical conductivity.
The applications of such a material are extensive and are already being exploited in tooling design and the automotive industry but the real benefits will be felt most strongly in aviation and space exploration.
I recently spoke to Billy Beggs, the Engineering Innovation Manager at the University of Central Lancashire (UCLan). Having spent decades working at British Aerospace, later to become BAE Systems, Beggs has a wealth of knowledge and experience of cutting edge aerospace development and his role at UCLan is to bring scientific research to practical fruition. He’s currently working with the team at UCLan that’s researching Graphene.
“Graphene’s strength and flexibility coupled with its excellent thermal and electrical conductivity provide numerous opportunities for use in aerospace,” he tells me.
Multi-Functional aircraft skin
It can be 3D printed, it has a 20% faster cure time than composites and has already been tried out as a skin on unmanned aerial vehicle (UAV) flight surfaces, sensors, antennas and even batteries.
“With the ability to create Graphene wiring layered directly into the wing and sensors built into the skin, you have the opportunity to make the aircraft flight surfaces multi-functional,” he explains.
Layering Graphene circuitry into the wings and printing sensor and antennas directly onto surfaces before applying a protective coating completely changes the way aircraft designers are able to think about the function of the skin with fewer constraints.
Lightning strike protection
An example of an application that can provide immediate benefit is lightning strike protection. Polymer based airframe structures aren’t conductive and so the existing answer is to use copper mesh layers, which protect the aircraft from strikes but add parasitic mass to the structure.
At a presentation on the subject at the recent Advanced Engineering show, Dr Adam Joesbury of Haydale Composites explained that Graphene provides the possibility of producing electroconductive composites, which perform the same function.
Haydale has demonstrated this technique successfully using nano-fillers within composite material, such as carbon black and Graphene. The company has developed a functionalisation process, which treats the nano-particles to enhance their existing electrical conductivity properties.
Currently, this is being used for non aviation applications such as EMI and electro-static discharge shielding as well as composite moulding tooling, where the thermal properties of Graphene are of advantage.
For aviation use, there is an extensive qualification process that needs to be followed before it can be used.
Graphene takes flight
I spoke to Beggs about the issues of qualification and whether this acts as a barrier to development. Acknowledging that the qualification of new materials and manufacturing processes is a necessary and lengthy exercise, he has a lot of experience of this and doesn’t see it as a barrier to development.
“My approach has always been to take new technology and get it into the air, try it out and see if it works as we expect it to. We use UAVs, non-safety critical components and balloon launches to test these materials, the important thing is to try them out,” he explains.
The first time Graphene took to the skies was at the Farnborough Air Show in 2016, when UCLan’s “Prospero” UAV attracted the attention of the aviation industry. Prospero is a three metre wide aircraft which is part constructed using a graphene enhanced carbon fibre material.
The Prospero flight was significant both for UKLan and the aviation industry. As a result of its success at the show, the University took a lead role in writing a strategy document on behalf of the Aerospace Technology Institute entitled “The Graphene Exploitation Strategy for the UK Aerospace Sector”, which highlights key opportunities for the UK to become a world leader in the use of graphene in the aerospace industry.
Juno – the next UAV
Since the Prospero success, UCLan has been working on its next Graphene UAV project, “Juno”, which supports the UK industrial strategy. The 3.5m wide Graphene skinned aircraft also has Graphene batteries and components that have been 3D printed.
So far, the project has been a static exhibit at events including the 2018 Farnborough Show but Beggs and the team at UCLan are keen to get it into the sky. Masters student Jake Jones took on the very challenging task of designing Juno during the final part of his BEng course in aerospace at UKLan.
Speaking about the reaction to Juno at the Farnborough event this year, Beggs says, “Having Juno at one the world’s biggest air shows demonstrates the great strides we’re making in leading a programme to accelerate the uptake of graphene and other nano-materials into industry.”
Juno is significant because of the extent to which Graphene has been used in its construction, including control and power elements as well as the skin. Putting it into the air will be a milestone test in the performance of the material in real flight conditions.
Graphene in space
In 2017, UKLan received funds from the UK Space Agency’s National Space Technology Programme to explore the practical use of the Graphene in the space industry. UKLan explored the benefits of Graphene enhanced carbon fibre composites for constructing satellites to make them lighter and stronger to reduce launch costs and the damage from space debris impacts.
To test this, the research team launched test balloons into the stratosphere with a payload of Graphene enhanced composite miniature satellites. Not only was the Graphene enhanced satellite 16% lighter than the standard one, it also had improved thermal properties, an important factor at the extremely low temperatures experienced at the edge of space.
Now, Beggs and the research teams at UKLan are continuing their programme of testing with more balloon launches to test Graphene antennas at high altitude and further development on Juno to truly get this exciting new material off the ground and into commercial service.
Graphene heads for the edge of space
Billy Beggs and Professor of Solar Physics, Robert Walsh couldn’t have chosen a better day for their latest experimental balloon launch, which I attended in the secluded Kentmere valley in South Lakeland.
Clear blue skies and low wind made launch conditions almost perfect for the 3m diameter helium-filled latex balloon, which was designed to catapult the experiment high into the stratosphere at a brisk rate of 5m per second.
The experiment consisted of two small Graphene antenna strips accompanied by a thermal insulating box containing GPS location instruments and sensors for measuring temperature and pressure. The box was attached to a parachute, which in turn was tethered to the balloon.
Made of extremely thin latex material, the balloon expands as the atmospheric pressure reduces with altitude. At the intended experiment height of 35km, the balloon reaches about 12m in diameter, at which point the latex gives way, the balloon disintegrates and the parachute and experiment return gracefully to earth.
During its journey, the Graphene experiences the effects of altitude, low atmospheric pressure and temperatures that could reach as low as -60C in the outer band of the earth’s atmosphere.
Once it returns to earth, data will be logged and the Graphene tested to compare its performance to a control sample and to non-Graphene composite antennas, taking the knowledge of the material a step further.